In construction machines with material handling capabilities, such as, wheel loaders, backhoe loaders and the like, pin joints are well known for attaching a lift arm or boom to the frame of the machine for utilization of a bucket or other implement. Generally, pin joints used for this function create forces on surrounding structure due to the relative movement of the lift arm or boom around the pin. Additionally, the pin may be deflected into point contact with the surrounding structure in such a manner that the pin is damaged. Managing the damaging effects of these forces and pin deflection usually requires the use of longer length to diameter bearing assemblies and larger pin diameters. Furthermore, joints must be lubricated at regular intervals in order to protect the pin joint from damage. Unfortunately, the lubrication of the pin joint must be completed every few hours during operation, which requires the time and energy of the operator. The operator also has the burden of maintaining this lubrication schedule without fail because of the potential harm that may occur to the machine.
One such design is disclosed in U.S. Pat. No. 5,769,557 issued on Jun. 23, 1998 to Charles E. Beals et al and is assigned to the owner of the present application. This design uses a sealed and lubricated pin joint with a profiled pin. The profiled pin is designed to make a line contact with the bearing and bushing components so as not to gall or gauge the pin.
The present invention is directed to overcoming the problems as set forth above.